Risk of Dental Disease Non-Battle Injuries and Severity of Dental Disease in Deployed U.S. Army Personnel

Transcription

1 MILITARY MEDICINE, 180, 5:570, 2015 Risk of Dental Disease Non-Battle Injuries and Severity of Dental Disease in Deployed U.S. Army Personnel Barbara E. Wojcik, PhD*; Wioletta Szeszel-Fedorowicz, PhD*; Rebecca J. Humphrey, MA*; LTC Paul Colthirst, DC USA* ; Alicia C. Guerrero, MPH*; John W. Simecek, DDS, MPH ; Adam Fedorowicz, PhD*; COL Steven Eikenberg, DC USA ; COL Georgia G. Rogers, DC USA ; COL Philip DeNicolo, DC USA ABSTRACT Dental Disease and Non-Battle Injuries (D-DNBI) continue to be a problem among U.S. Army active duty (AD), U.S. Army National Guard (ARNG), and U.S. Army Reserve (USAR) deployed soldiers to Operation Iraqi Freedom/Operation New Dawn in Iraq and Operation Enduring Freedom in Afghanistan. A previous study reported the annual rates to be 136 D-DNBI per 1,000 personnel for AD, 152 for ARNG, and 184 for USAR. The objectives of this study were to describe D-DNBI incidence and to determine risk factors for dental encounters and high severity diagnoses for deployed soldiers. The 78 diagnoses were classified into three categories based on severity. Poisson regression was used to compare D-DNBI rates and logistic regression was used to analyze the risk of high severity D- DNBI. In both campaigns, Reserve had a higher risk of D-DNBI than active duty. For Afghanistan, ARNG and USAR demonstrated over 50% increased risk of D-DNBI compared to AD. In Iraq, USAR had a 17% increased risk over AD. Females had a higher risk of D-DNBI (>50%) compared to males in both campaigns. High severity D-DNBI made up 2.77% of all diagnoses. Within Afghanistan, there was a 4.6% increased risk of high severity D-DNBI for each additional deployment month. INTRODUCTION Ensuring a healthy and fit-to-fight-force is paramount to the success of the U.S. Military. Oral diseases and conditions can cause severe pain and dysfunction that interferes with a soldier s ability to eat, communicate, sleep, or concentrate on the task at hand, and can sometimes become life-threatening if not treated. Dental emergencies, alternatively referred to as Dental Disease Non-Battle Injuries (D-DNBI), are defined as any unscheduled oral or craniofacial issue perceived by the soldier to be a problem, which causes them to seek the help or advice of a dental officer. 1 Soldiers removing themselves *Center for AMEDD Strategic Studies, 2478 Stanley Road, Suite 47, ATTN: MCCS-FH, Fort Sam Houston, TX Tri-Service Center for Oral Health Studies, 2787 Winfield Scott Road, Suite 220, Fort Sam Houston, TX Naval Medical Research Unit San Antonio, 3650 Chambers Pass, Fort Sam Houston, TX Army Medical Department (AMEDD) Center and School, 3599 Winfield Scott RD, Suite 600, Fort Sam Houston, TX kaberdeen Proving Ground Dental Clinic Command, 2501 Oakington Street, Aberdeen Proving Ground, MD Dental Trauma Research Detachment, Institute of Surgical Research, 3650 Chambers Pass, Fort Sam Houston, TX The authors are military service members or employees of the U.S. Government. This work was prepared as part of the authors official duties. Title 17 U.S.C. 105 provides that Copyright protection under this title is not available for any work of the United States Government. Title 17 U.S.C. 101 defines a U.S. Government work as a work prepared by a military service member or employee of the U.S. Government as part of that person s official duties. The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Departments of the Army or Navy, the Department of Defense, or the U.S. Government. doi: /MILMED-D from their duty station because of dental problems can impact overall unit effectiveness and affect the ability of the deployed force to achieve mission success. Seeking care for a D-DNBI can also be a danger to the soldier and other personnel required to escort the casualty to a dental clinic in a hostile environment with an active insurgency. One soldier experiencing a D-DNBI can require up to nine personnel and a convoy of three vehicles to evacuate the soldier to receive necessary care. 2 Published reports reveal a wide range of D-DNBI rates in military personnel. Rates reported for personnel in combat and stabilization operations varied from 111 to 437 per 1,000 personnel per year Some of the variability in rates is because of differences in study design, observation periods, dental class status, and access to clinical services due to environmental and operational challenges. 12 The annual rates varied by component and were reported in a previous study as 136 D-DNBI per 1,000 personnel for U.S. Army active duty (AD), 152 for U.S. Army National Guard (ARNG), and 184 for U.S. Army Reserve (USAR). 13 The D-DNBI rates in recent campaigns are much higher than medical DNBI admission rates calculated by Wojcik et al, 14 a fact that prompts further analysis on how to improve dental readiness and lower dental emergency incidence rates in theater. Although many of the aforementioned studies examined the frequencies of different types of D-DNBI, most did not attempt to determine the severity of each D-DNBI based on the expected morbidity or length of time required for treatment. However, one study did report that approximately 20% of all D-DNBI would be of sufficient severity to cause a limitation of operational capability. 15 Few studies have addressed risk factors for D-DNBI occurring in military personnel. Serious unmet dental needs 570 MILITARY MEDICINE, Vol. 180, May 2015

2 have been shown to be associated with higher D-DNBI rates. In 1987, Teweles and King 16 reported an eight-fold increased rate of D-DNBI for soldiers during a 22-week peacekeeping operation in Sinai. Soldiers who were classified in the highrisk category before deployment had an extrapolated annual D-DNBI rate per 1,000 soldiers of 530 dental emergencies. The same D-DNBI estimate for soldiers classified before deployment in the no dental treatment needed category was 67 dental emergencies per 1,000 soldiers per year. Richardson 17 reported that high-risk U.K. soldiers supporting Operation Telic in 2003 were at 3.87 times the risk of a D-DNBI as those who were considered moderate or low risk for D-DNBI at predeployment. A retrospective cohort study of the dental records of U.S. Marine Corps personnel reported that the number of missing and filled teeth, as well as the number of third molars present at the initial examination was associated with an increase in D-DNBI. 18 In dental clinics providing routine and emergency care, any dental condition that leads a soldier to seek care is considered a D-DNBI. Within ongoing, complex operations such as Operations Iraqi Freedom/Operation New Dawn (OIF/ OND) and Operation Enduring Freedom (OEF), a system that can account for all D-DNBI and distinguish the severity of each is extremely important. Data describing both the etiology and severity of D-DNBIs occurring during combat can provide medical planners the information necessary to determine the size and skill composition of the dental footprint for future operations. Although an established etiology classification of D-DNBI exists, a defined severity classification is lacking. The primary objective of this retrospective study was to provide the incidence and profiles of dental emergencies in theater based on collected data and to examine factors that influence D-DNBI incidence rates among Army active duty, ARNG, and USAR soldiers deployed to Iraq in support of OIF/OND and Afghanistan in support of OEF. The overall aim of this comprehensive study is to clinically and scientifically quantify the types of disease and problems seen in deployed setting with the intent of improving predeployment screening policies. Additionally, this study aimed to examine dental diagnoses using a novel 3-tier categorization schema to determine the severity of the D-DNBI. Finally, potential risk factors associated with high severity diagnoses were evaluated to describe differences in severity categories for different Army components. METHODS AND MATERIALS Data Description The Corporate Dental Application was used to electronically collect D-DNBI information. Army dental officers documented all dental encounters occurring in U.S. Army soldiers deployed to Iraq and Afghanistan at the point of service within Army dental clinics located in Iraq (OIF/OND) and Afghanistan/Kuwait (OEF). Dental conditions that had a treatment code of A0199 (dental emergency) or the Current Dental Terminology reference code D0140 (problem-focused dental examination) were documented and described by the dental officers. The Dental Emergency Encounter Entry module is a separate feature within the Corporate Dental Application that allows entry of detailed clinical descriptions of D-DNBI. This module describes each D-DNBI by diagnosis and etiology group. There are 78 diagnoses, each assigned to one of seven etiology groups relating cause to condition: enamel, dentin, or restoration; periodontal condition; pulpal disease condition; temporomandibular disorder; dentoalveolar surgery or third molar retention/removal; external trauma; and other dental conditions. Eikenberg and colleagues describe the process that was undertaken to implement the described above collection module in theater and to validate the documented D-DNBI data for reliability. 19 The Center for Army Medical Department Strategic Studies (CASS) receives the D-DNBI data on a monthly basis. Once received, the data are evaluated by statisticians who perform quality assurance checks, conduct numerous statistical analyses, and compile the information into summary reports that are made available on the CASS Dental Encounters Report System website to Department of Defense personnel. 20 This website is developed and maintained by CASS analysts. The 78 diagnoses used in the dental module were classified into three categories based on the severity of D-DNBI: low, moderate, and high. A comprehensive list of dental diagnoses by the levels of severity is presented in Table I. The high severity category was defined as D-DNBI that would result in at least moderate-to-severe pain, infection, or loss of function and which could, if left untreated, result in a life-threatening condition. Examples of high severity conditions are anatomic space infections, necrotizing ulcerative gingivitis, fractured facial bones, and other trauma-related problems that led to evacuation or referral for advanced care. The moderate-severity category consists of D-DNBI that would cause moderateto-severe pain, infection, or loss of function, but that would not result in a life-threatening condition if left untreated. All other D-DNBI diagnoses are labeled as low severity and were associated with conditions causing less than moderate pain and infection or loss of function that could be tolerated by patients until dental support was available. Study Design This retrospective study was limited to D-DNBI encounters of U.S. Army service members: active duty, National Guard, and Reserve during deployment to Iraq and Afghanistan. Soldiers may have multiple encounter records if they returned for follow-up treatment or experienced another D-DNBI. Therefore, the number of encounters was greater than the number of soldiers presenting with a dental emergency. Additionally, soldiers can have multiple diagnoses in one encounter resulting in a higher number of diagnoses than encounters or soldiers. MILITARY MEDICINE, Vol. 180, May

3 TABLE I. List of the 78 Dental Disease and Non-Battle Injury Diagnoses Categorized by Severity Levels (a) High Severity (1) Anatomic space infection (periodontal origin) (2) Necrotizing ulcerative gingivitis (3) Anatomic space infection (4) Anatomic space infection with amalgam restoration (endodontic origin) (5) Anatomic space infection with composite restoration (endodontic origin) (6) Anatomic space infection with no restoration (endodontic origin) (7) Anatomic space infection with temporary restoration (endodontic origin) (8) Anatomic space infection (unrelated to pulpal problem) (9) Fractured facial bones or mandible due to trauma regardless of disposition status (10) Fractured tooth or teeth due to trauma regardless of disposition status (11) Hemorrhage (12) Partially avulsed teeth due to trauma regardless of disposition status (13) Totally avulsed teeth due to trauma regardless of disposition status (14) Soft tissue abrasion, laceration, or contusion due to trauma a (15) Other trauma related problem a (16) Acute herpetic gingivostomatitis (17) Swelling of undetermined origin (18) Oral infection or abscess of undetermined origin a (b) Moderate Severity (1) Alveolar osteitis (2) Ailing/Falling implants (3) Candidiasis (4) Defective broken prosthesis, permanent (5) Defective broken prosthesis, provisional (6) Myofascial pain (7) Necrotic pulp (8) Other orofacial pain (9) Pain of undermined origin (10) Periradicular periodontitis (11) Periodontal abscess (12) Pulpless/previously treated (13) Pulpitis (14) Pulpitis with amalgam restoration (15) Pulpitis with composite restoration (16) Pulpitis with no restoration (17) Pulpitis with temporary restoration (18) Periodontal/ gingival problem (19) Periradicular abscess (20) Periradicular abscess with amalgam restoration (21) Periradicular abscess with composite restoration (22) Periradicular abscess with no restoration (23) Periradicular abscess with temporary restoration (24) Periradicular periodontitis (25) Other orofacial pain disorder (26) Pericoronitis (27) Sequestrum from previous extraction (28) Soft tissue abrasion, laceration, or contusion, which does not require any higher level of care or evacuation from theater (29) Temporomandibular problem (30) Other trauma related dental problem, which does not require higher level of care or evacuation from theater (31) Oral tumor, cysts or growth (32) Other oral or dental condition (continued) TABLE I. Continued (c) Low Severity (1) Defective/missing restoration (2) Defective/missing restoration with amalgam restoration (3) Defective/missing restoration with composite restoration (4) Defective/missing restoration with temporary restoration (5) Eruption pain (6) Fractured tooth/restoration (7) Fractured tooth/restoration with amalgam restoration (8) Fractured tooth/restoration with composite restoration (9) Fractured tooth/restoration with no restoration (10) Fractured tooth/restoration with temporary restoration (11) Defective/missing restoration (12) Defective/missing restoration with amalgam restoration (13) Defective/missing restoration with composite restoration (14) Defective/missing restoration with temporary restoration (15) Fractured tooth/restoration (16) Fractured tooth/restoration with amalgam restoration (17) Fractured tooth/restoration with composite restoration (18) Fractured tooth/restoration with no restoration (19) Fractured tooth/restoration with temporary restoration (20) Dental caries (21) Tooth or restoration in hyperocclusion (22) Dental hypersensitivity (23) Other tooth related problem of enamel, dentin or restoration etiology (24) Gingivitis/gingival bleeding (25) Postoperative pain (26) Other dentoalveolar problem (27) Other dentoalveolar problem (28) Aphthous ulceration a Disposition status indicating higher level of care is defined as: Transport to higher level of care in theater or Evacuate from theater. For the purpose of this study, separate analyses were performed for Iraq and Afghanistan. D-DNBI analysis for Iraq used encounter data collected from May 1, 2009 through December 31, 2011 (the end of Operation New Dawn in Iraq), whereas analysis for Afghanistan used encounter data collected from January 1, 2011 through December 31, The starting dates differ between Iraq and Afghanistan because data collection began on different dates. Descriptive analyses of the study population included frequency distributions of U.S. Army soldiers by gender, age group, component, unit category, and military rank group. Additionally, frequency distributions of severity categories for D-DNBI and the most frequently experienced high severity diagnoses were both determined and stratified by component. 572 MILITARY MEDICINE, Vol. 180, May 2015

4 Military characteristics and demographic features were included in the regression models to control for factors potentially associated with in-theater D-DNBI. The OIF/OND and OEF campaigns were modeled separately using the same set of independent variables. Risk analysis was conducted using multivariate Poisson regression, with five independent variables included in the regression models of D-DNBI: gender, age group, component, unit category, and military rank group. Reference categories used were males, the 20 to 29 age group, active duty component, combat unit, and officer rank. Poisson models were corrected for overdispersion using the Pearson scaling factor. Additionally, multivariate logistic regression was applied to analyze the risk of a high severity dental diagnosis across component, gender, unit category, and deployment time. Dental diagnoses were coded by severity categories as follows: (1) high, (2) moderate, and (3) low. For the logistic regression analysis, only one diagnosis, based on highest severity level, was retained for soldiers who had multiple diagnoses documented in an emergency D-DNBI encounter. Emergency dental encounter data for soldiers with unspecified severity and unknown unit category were removed from the model. All data analyses were performed using SAS software version 9.3. Relative risks were determined using the SAS GENMOD and LOGISTIC procedures. In all analyses, p values less than 0.05 were considered significant. This study was conducted under a protocol (United States Army Institute of Surgical Research Protocol number: H ) that was reviewed and approved by the U.S. Army Medical Research and Materiel Command Institutional Review Board. CASS receives dental data on a regular basis in accordance with an established data use agreement. Data used by CASS were obtained and analyzed following strict data governance rules approved by the Army Human Research Protection Office: records were limited in scope to variables needed for the stated purposes and deidentified. All personally identifiable information were removed to protect soldier identity and prevent rematch of personal health information back to individual patients. All datasets were protected on secure Department of Defense servers. RESULTS In Iraq (OIF/OND), 21,620 soldiers were seen for a total of 27,846 D-DNBI encounters, and 9,412 soldiers were seen for a total of 11,454 dental emergencies in Afghanistan and the staging area of Kuwait (OEF). In both campaigns, male soldiers constituted the majority (84%) of D-DNBI patients (Table II) and about 90% of the deployed force. Soldiers between 20 and 29 years of age were the most frequent age group seeking dental emergency care (55%) in both Iraq and Afghanistan; they constituted over 60% of forces deployed to Iraq and over 58% of soldiers deployed to Afghanistan. In both campaigns, active duty consisted of around 65% of U.S. Army soldiers seeking emergency dental care, followed by National Guard (around 24%), and Reserve (about 12%). TABLE II. Demographics of U.S. Army Soldiers Who Had Dental Emergency Encounters in OIF/OND (May 1, 2009 to December 31, 2011) and OEF (January 1, 2011 to December 31, 2012) OIF/OND (n = 21,620) OEF (n = 9,412) Characteristics n % n % Gender Male 18, , Female 3, , Age Group <20 1, , , , , , , Unknown Component Active Duty 13, , National Guard 5, , Reserve 2, , Unit Category Combat 9, , Combat Support 3, , Combat Service 6, , Support Medical Unknown Grade Group Enlisted 18, , Officer 3, , Unknown OIF, Operation Iraqi Freedom; OND, Operation New Dawn; OEF, Operation Enduring Freedom. However, the unit category distribution of soldiers differed for Afghanistan compared to Iraq; there were less medical and combat service support personnel proportionately in Afghanistan compared to Iraq: 3.21% versus 4.36%, and 25.93% versus 30.50%, respectively. For both campaigns, the vast majority of soldiers with D-DNBI were enlisted (84%); enlisted soldiers represented over 85% of all deployed troops in both Iraq and Afghanistan. D-DNBI Risk Analysis The Poisson regression models identified several significant risk factors associated with D-DNBI for both operations. Results of both models are presented in Table III. Both Reserve and National Guard demonstrated a higher risk of experiencing dental emergencies than active duty after adjusting for gender, age group, unit category, and rank group. In Iraq, the increased risk was 17% for Reserve and a nonsignificant 2% for National Guard. In Afghanistan, the increased risk of having dental emergencies was more pronounced: 51% for Reserve and 73% for National Guard than for active duty soldiers. Significant relative rate differences for D-DNBI were also found among gender, age group, and unit category assignments in both Iraq and Afghanistan. Women serving in Iraq demonstrated a 54% higher risk of MILITARY MEDICINE, Vol. 180, May

5 TABLE III. Results of Poisson Regression of Dental Disease and Non-Battle Injuries in Operation Iraqi Freedom/New Dawn (May 1, 2009 to December 31, 2011) and Operation Enduring Freedom (January 1, 2011 to December 31, 2012) Operation Iraqi Freedom/Operation New Dawn Operation Enduring Freedom Characteristics RR p* 95% CI RR p* 95% CI Gender Female/Male 1.54 < < Age Group <20/20 to to 39/20 to to 49/20 to < < /20 to < < Component National Guard/Active Duty < Reserve/Active Duty 1.17 < < Unit Category Combat Support/Combat Combat Service Support/Combat a 1.12 < < Medical/Combat a 1.69 < < Grade Enlisted/Officer < Reference categories: Male, 20 to 29 age group; Active Duty; Combat Unit and Officers. RR, relative risk; CI, confidence interval. a Medical category was extracted from the Combat Service Support Category. *Values in boldface imply statistically significant RR at the 0.05 level of significance. having a dental emergency compared to men and had a 76% higher risk than males in Afghanistan. Soldiers 40 to 49 years and over 50 years old had 25% and 45% higher risks of dental emergencies, respectively, compared to 20- to 29-year-olds in OIF/OND. The risk for the same age groups in OEF was 32% and 80% higher compared to 20- to 29-year-olds. In Iraq, soldiers assigned to combat support, combat service support, and medical units (personnel assigned to medical units were identified and extracted from the combat service support category) all had significantly higher D-DNBI rates compared to combat units: 12%, 12%, and 69% higher risk, respectively. In Afghanistan, soldiers in combat service support and medical units also had significantly higher risks of D-DNBI compared to combat units: 24% and 98% higher, respectively. There was a 7% increase in the risk of D-DNBI for enlisted versus officers in Iraq, and a 16% higher risk in Afghanistan. Severity of D-DNBI Both campaigns demonstrated similar D-DNBI severity profiles (Table IV). The total number of diagnoses in both campaigns was distributed as follows: 2.77% of diagnoses were of high severity (1,291), 21.47% were moderate (10,006), and 75.76% were considered low severity (35,312). In Iraq, Reservists had the highest percentage of high severity diagnosis among all the components (2.93% active duty, 2.76% National Guard, and 3.11% Reserve). For soldiers deployed to Afghanistan and treated with high severity D-DNBI diagnoses, TABLE IV. Severity Categories of Dental Disease and Non-Battle Injury Diagnoses for U.S. Army Soldiers Deployed in OIF/OND (May 1, 2009 to December 31, 2011) and OEF (January 1, 2011 to December 31, 2012) by Component Active Duty National Guard Reserve Total U.S. Army Severity n % n % n % n % OIF/OND a High Moderate 4, , , Low 15, , , , Unspecified Total 20, , , , OEF b High Moderate 2, , Low 6, , , , Unspecified Total 9, , , , OIF, Operation Iraqi Freedom; OND, Operation New Dawn; OEF, Operation Enduring Freedom. a There is a statistically significant relationship between severity and U.S. Army component in OIF/OND: c 2 = 20, 41, df = 6, p = b There is a statistically significant relationship between severity and U.S. Army component in OEF: c 2 = 15.20, df = 4, p = MILITARY MEDICINE, Vol. 180, May 2015

6 the distribution across components was 2.65% AD, 2.10% ARNG, and 1.64% USAR. Active duty soldiers presented almost a 10% lower proportion of high severity diagnoses in Afghanistan compared to Iraq. Reservists in OEF experienced nearly half the proportion of high severity diagnoses as Reservists in OIF/OND (1.64% as compared to 3.11%, respectively) and went from being the group with the highest percentage of high severity D-DNBI in Iraq to the group with the lowest percentage in Afghanistan. National Guard soldiers demonstrated a 24% lower proportion of high severity D-DNBI in Afghanistan than in Iraq. To provide perspective on the types of high severity D- DNBI, the three most frequently observed diagnoses of high severity by component for both campaigns are presented in Table V. Of all 17 high severity diagnoses, the three most common diagnoses were the same in OND in both Iraq and Afghanistan: necrotizing ulcerative gingivitis, anatomic space infection of endodontic origin, and fractured tooth. In Iraq, the distribution of the three most frequent high severity diagnoses were (1) necrotizing ulcerative gingivitis as 39.68% of all high severity diagnoses, (2) fractured tooth (16.19%), and (3) anatomic space infection of endodontic origin (13.23%). Together these three diagnoses made up 69.10% of all high severity diagnoses in OIF/OND. All component groups within Iraq had the same rank order of high severity diagnoses. The top three high severity diagnoses made up 80.32% of all the high severity diagnoses for USAR, whereas they constituted about 67.66% for AD and 65.50% for ARNG. In Afghanistan, the rank order of high severity diagnoses differed compared to Iraq; fractured tooth was the most frequently experienced diagnosis with 45.42%, followed by both anatomic space infection of endodontic origin (15.36%) and necrotizing ulcerative gingivitis (15.36%), which were equally ranked. Interestingly, the percentage of severe diagnoses of fractured tooth was 2.8 times higher in Afghanistan than in Iraq (45.42% versus 16.19%). On the contrary, the most common severity diagnosis in Iraq was necrotizing ulcerative gingivitis, and the relative proportion was 2.6 TABLE VI. Logistic Regression Results Predicting a High Severity Dental Disease and Non-Battle Injury Among U.S. Army Soldiers Deployed to Iraq (May 1, 2009 to December 31, 2011) and Afghanistan (January 1, 2011 to December 31, 2012) Operation Iraqi Freedom/ Operation New Dawn Operation Enduring Freedom Characteristic OR (95% CI) OR (95% CI) Gender Male (Reference) Female 0.766* (0.622, 0.933) (0.539, 1.153) Component Regular (AD) (Reference) National Guard (0.795, 1.099) (0.639, 1.203) Reserve ( 0.835, 1.290) 0.496* (0.269, 0.846) Unit Category Combat (Reference) Combat Support (0.740, 1.110) (0.572, 1.152) Combat Service (0.946, 1.288) (0.684, 1.203) Support a Deployed Months (0.971, 1.009) 1.046* (1.008, 1.086) OR, odds ratio; CI, confidence interval. a Medical units were included in the Combat Service Support category in this analysis. *Statistically significant at 0.05 probability of error. times higher in Iraq than in Afghanistan (39.68% versus 15.36%). Risk of High Severity Dental Disease Logistic regression analysis was used to evaluate the risk of a high severity D-DNBI using a model that accounted for differences in gender, component, unit category, and reported months of current deployment at the time of D-DNBI. The results of the logistic regression analysis are reported in Table VI. The OIF/OND model revealed only gender as a significant factor in estimating the risk of a high severity dental disease with female soldiers having a 23% lower risk than men (odds ratio [OR]: 0.766; 95% confidence interval [CI]: 0.622, TABLE V. Three Most Frequently Reported High Severity Diagnoses for U.S. Army Soldiers Deployed in OIF/OND (May 1, 2009 to December 31, 2011) and OEF (January 1, 2011 to December 31, 2012) by Component Diagnoses a n % n % n % n % AD National Guard Reserve Total U.S. Army OIF/OND Necrotizing Ulcerative Gingivitis Fractured Tooth Anatomic Space Infection-Endodontic Total OEF Fractured Tooth Anatomic Space Infection-Endodontic Necrotizing Ulcerative Gingivitis Total OIF, Operation Iraqi Freedom; OND, Operation New Dawn; OEF, Operation Enduring Freedom. a We are presenting only three most frequent diagnoses by component; therefore, percentages will not add to 100%. MILITARY MEDICINE, Vol. 180, May

7 0.933) holding all other factors equal. For soldiers deployed in support of OEF, the significant predictors of high severity D- DNBI were component and deployment time. The Reservists had an approximately 50% lower risk for high severity diagnoses compared to active duty in Afghanistan, whereas in Iraq the Reserve had a slightly higher (nonsignificant) risk than AD. For every additional month of deployment in Afghanistan, there was a 4.6% increase in risk (OR: 1.046; 95% CI: 1.008, 1.086). However, deployment time was not a significant predictor in Iraq. DISCUSSION D-DNBI are not experienced equally across deployed Army forces. Significant differences in D-DNBI among components were observed in this study, even after accounting for other factors such as gender, age group, unit category, and rank group. Results of the analysis indicate that Reserve soldiers had a higher risk of D-DNBI compared to active duty in both operations. Higher risk of a D-DNBI in Afghanistan than in Iraq (51% versus 17%) may be explained by lower dental emergency rates for active duty in Afghanistan compared to Iraq. These AD rates were used as a benchmark category when assessing relative risk. The National Guard demonstrated an increased risk in Afghanistan. Among unit categories, combat service support and medical support groups had a higher risk of D-DNBI than combat units. Differences in D-DNBI among gender and unit category might be explained by differences in access to dental clinics. Female soldiers were at a higher risk of any D-DNBI compared to men; however, female soldiers had a lower risk of high severity D-DNBI. This was probably due to their having better predeployment dental conditions than the men. Dental treatment delivered in theater suggests women tend not to engage in deleterious oral habits such as chewing tobacco, dipping, and smoking as do many male soldiers. Furthermore, females are often attached to units in a combat support role or medical support units that are usually found on large Forward Operating Bases. So it is quite conceivable to assume that having access to dental clinics will increase access and utilization of dental services. On the other hand, combat units serving in field operations are usually in remote areas far away from dental services. Also, soldiers in combat units may delay seeking dental care when they have to travel great distances to a dental clinic. During this period of delay, oral problems could exacerbate and become severe. In essence, these remotely stationed soldiers could be waiting until they develop multiple dental problems before seeking care compared to soldiers who are colocated with the dental clinics. Male soldiers, soldiers in age group 20 to 29 years, and enlisted soldiers represented the highest percentage of those who were deployed (50.5% of deployed forces in Afghanistan and 48.5% in Iraq) and who had to seek dental emergency care (42.7% in Afghanistan and 43.1% in Iraq). But being a male or between the age of 20 and 29 years did not increase the risk of dental emergency. Only enlisted soldiers TABLE VII. Dental Readiness Class 1 Rates Among U.S. Army Soldiers Over Time (December 2009 to December 2012) December 2009 December 2010 December 2011 December 2012 Active Duty 19.6% 20% 23.2% 29% USAR 14.6% 18.8% 18.8% 19% Guard 16.3% 19.1% 24.8% 27.8% demonstrated some increase in dental emergency incidence compared to officers (7% increased risk in Iraq and 16% increased risk in Afghanistan). Decreases in D-DNBI rates over time for both theaters 13 may have been as a result of improvements in Dental Readiness Class 1 (DRC 1) status (dental wellness, no dental treatment needs). DRC 1 rates obtained from the Army s Medical Protection System for all Army components at various points in time are shown in Table VII. DRC 1 soldiers are the least likely to experience a dental emergency, so improvements in the soldier population at large may have been mirrored in the deployed forces in our study and yielded improvements. This possibility would have to be explored in a future analysis. Results presented here suggest that the majority of dental needs in theater for Iraq and Afghanistan were mild and could be easily treated if dentists were available. In each operation, approximately 24% of the D-DNBI diagnoses were of high or moderate severity, similar to the 25% previously reported to be true dental emergencies in Bosnia in Soldiers with dental emergencies of high and moderate severity are potential candidates for medical evacuation from theater. It would be expedient to lower the percentage of soldiers with D-DNBI in these two severity groups by improving their timely predeployment screening and treatment. The three most common high severity diagnoses were the same for both campaigns: necrotizing ulcerative gingivitis, anatomic space infection of endodontic origin, and fractured tooth. Interestingly, although USAR soldiers experienced significantly higher risk of a D-DNBI compared to AD, this group demonstrated significantly lower risk of a severe D-DNBI diagnosis in Afghanistan. On the basis of the results presented in our study, within Afghanistan, conditions of high severity could be partially explained by increasing deployment time. Although the high severity D-DNBI consisted of less than 3% of total diagnoses, soldiers had a 4.6% increase in risk for each additional month of deployment. This result may suggest that completing all required dental care at a predetermined point before soldiers departures to theater may reduce the risk of future dental emergencies at the rate of almost 5% per month. However, additional analysis is needed to further explore this finding. The findings of this study highlight the need for continued dental care across the 3 Army components. Additionally, the results reveal that soldiers who were deployed to OEF had lower annual D-DNBI emergency encounter rates than those 576 MILITARY MEDICINE, Vol. 180, May 2015

8 who served in OIF/OND. The lower dental emergency rates in OEF may not be a true reflection of dental needs because access to dental clinics is restrictive because of the immaturity of the Afghanistan theater when compared to the availability of dental care for soldiers in Iraq. This finding is similar to what is seen in rural areas within the United States. Rural areas have fewer dentists, lower dental utilization rates, and higher dental needs. Because of the difficult terrain found in Afghanistan, the underdevelopment of its infrastructure and great distance to combat outposts, dental assets are sparse, thus resembling a rural dental setting. This study was limited to the dental emergency data collected in deployed settings. We plan to expand this analysis in the future to examine the impact of the predeployment dental readiness, the time between the dental classification examination and deployment, and the course of treatment before deployment, to include the time of the last predeployment dental visit; as well as last deployment time. This type of investigation would warrant another comprehensive study, and the results could link the predeployment status with the scope and severity of dental emergencies in theater, to include the most severe diagnoses such as endodontic infections and fractured teeth. CONCLUSION To our knowledge, this is the first study that provides comprehensive information about the magnitude and characteristics of D-DNBI encounters among U.S. Army soldiers deployed to Iraq and Afghanistan and illuminates population risk factors that affect D-DNBI rates. In addition, this study investigated potential risk factors to explain high severity D-DNBI. Using a severity categorization schema to analyze D-DNBI allows medical planners to consider the types of dental care to expect in a deployed setting and plan accordingly. Given the results presented here, it would be beneficial to continue the surveillance of D-DNBI in deployed personnel to identify reasons for existing differences among U.S. Army components and further examine and characterize dental disease occurrence in deployed settings. Conditions that may contribute to increased risk of high severity dental disease linked to deployment time also merit further investigation. Results of this study may help to develop new strategies and procedures to better deliver care pre- and during deployment in order to improve soldiers readiness and decrease dental emergency incidence in deployed setting. Finally, the development of a predictive dental model accounting for both etiology and severity would be highly beneficial for military planners. REFERENCES 1. 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